CVE-2014-1840 in MyBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Upload/search.php in MyBB 1.6.12 and earlier allows remote attackers to inject arbitrary web script or HTML via the keywords parameter in a do_search action, which is not properly handled in a forced SQL error message.
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Analysis
by VulDB Data Team • 05/23/2017
The vulnerability identified as CVE-2014-1840 represents a critical cross-site scripting flaw within the MyBB forum software version 1.6.12 and earlier. This weakness resides in the Upload/search.php script where the keywords parameter fails to properly sanitize user input during search operations. The vulnerability becomes exploitable when attackers craft malicious payloads that leverage the do_search action, which then triggers a forced SQL error message that does not adequately filter or escape the injected content. This particular implementation flaw demonstrates a classic XSS vulnerability that falls under CWE-79, which specifically addresses improper neutralization of input during web page generation.
The technical execution of this vulnerability occurs when an attacker submits specially crafted input through the keywords parameter in the search functionality. When the system processes this input and encounters a SQL error condition, the malformed data gets embedded into the error message without proper HTML escaping or sanitization. This creates an environment where malicious scripts can be executed within the context of other users' browsers, effectively enabling attackers to hijack user sessions, steal cookies, or redirect victims to malicious sites. The attack vector is particularly insidious because it leverages legitimate error handling mechanisms rather than direct injection points, making detection more challenging for security monitoring systems.
The operational impact of this vulnerability extends beyond simple script execution to encompass potential session hijacking and data exfiltration capabilities. When exploited successfully, attackers can manipulate forum users' browsing experiences by injecting malicious JavaScript that executes in their browsers, potentially leading to unauthorized access to private forums, posting of spam content, or even credential theft. The forced SQL error message mechanism creates a unique attack surface where the error output itself becomes the vector for XSS delivery, which is particularly concerning given that error messages are typically expected to be safe and informative rather than potentially malicious. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter usage, as attackers can leverage the injected scripts to perform further malicious activities within the compromised user sessions.
Organizations running affected MyBB versions should immediately implement multiple layers of defense to mitigate this vulnerability. The most immediate solution involves patching the software to version 1.6.13 or later where the input sanitization has been properly addressed. Additionally, administrators should implement proper input validation and output encoding mechanisms, particularly around the search functionality where user input is processed. Web Application Firewalls should be configured to detect and block suspicious patterns in search parameters, and regular security audits should be conducted to ensure that all user-supplied inputs are properly sanitized before being processed or displayed. The remediation process should also include monitoring for unusual search patterns that might indicate exploitation attempts, as this vulnerability can be leveraged for both direct attacks and as part of broader reconnaissance efforts targeting forum communities.